JPH0233436A - Fuel supply control device for vehicle - Google Patents

Abstract

PURPOSE:To prevent the degradation of the engine startup and the generation of the defective ignition of an ignition plug by forming such as to inhibit the increase of the fuel supply quantity at the initial engine startup in case of discriminating the execution of the engine restart before the termination of the engine startup. CONSTITUTION:A control circuit 4 is provided with a temporary memory means for temporarily memorizing the execution of increasing the fuel supply quantity in the initial startup of an engine, a startup termination discriminating means for discriminating the normal running state after the termination of the engine startup and a restart discriminating means for discriminating whether or not the engine startup is executed a second time before the termination of the engine startup is discriminated by the startup termination discriminating means. An increase inhibiting means for inhibiting the increase of the fuel supply quantity at the initial engine startup is further provided for the case of discriminating the execution of the engine restart before the termination of the engine startup. As a result, the supplied fuel at the time of the engine startup is prevented from being excessive.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel supply amount control device for a vehicle that eliminates the inconvenience caused when an engine is repeatedly started.

(Prior Art) Conventionally, what is called a fuel control W device or an air-fuel ratio control device that controls the amount of fuel supplied according to the operating state of the engine includes a device that increases the amount of fuel supplied at the initial stage of engine startup. (For example, as shown in Japanese Patent Laid-Open No. 100044/1983). The purpose of this is to supply a larger amount of fuel than the amount of fuel supplied after the engine warms up, since the engine is cold when the engine is started, so that the engine can start smoothly.

(Problems to be Solved by the Invention) However, in the conventional example, when starting the engine, the ignition switch is turned on and off repeatedly in a short period of time, or the starter is activated many times in a short period of time. When the engine starting operation, such as starting the engine, is repeated, the fuel increase correction at the initial stage of engine starting is executed each time. For this reason, there is a risk that the fuel will be excessive, resulting in deterioration in engine startability and ignition failure of the ignition plug. Furthermore, the amount of fuel supplied is increased unnecessarily, resulting in wasteful consumption of fuel.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention temporarily stores that the amount of fuel supply m has been increased at the initial stage of engine startup.
・A time storage means, a start end determination means for determining that the engine start has ended and the normal operating state has been reached, and a start end determination means for determining that the engine start has ended before the start determination means determines that the engine start has ended again. a restart determination means for determining whether or not the engine has been restarted; and if the restart determination means determines that the engine has been restarted before the end of the engine start, a fuel supply at the initial stage of engine startup; and an increase prohibiting means for prohibiting an increase in the amount.

(Function) As described above, even if the engine is restarted repeatedly before the engine start is completed, the present invention prevents an increase in the amount of fuel supplied at the initial stage of engine startup for the restart. It is possible to prevent excess fuel from being supplied at the time.

Embodiment FIG. 1 is a schematic diagram of a vehicle fuel supply amount control device according to an embodiment of the present invention.

A fuel injection valve 6 is provided in the intake pipe 1 leading to the engine cylinder 10, and an intake pipe pressure sensor 2 for detecting the intake pipe pressure after being throttled by the throttle valve 7 is connected to the bypass passage 9. connected via. Further, the engine cylinder 10 is provided with a crank angle sensor 3 that generates a pulse signal in accordance with the rotational speed of the engine crankshaft.
A water wetness sensor 5 for detecting engine cooling water temperature is also provided.

The outputs of the intake pipe pressure sensor 2, crank angle sensor 3, and water temperature sensor 5 are input to a control circuit 4. As shown in FIG. 2, this control circuit 4 includes CP, U 14 and RO.
This is a microcomputer control circuit configured using M16 and RAM17.

The level correction circuit 12 corrects the levels of the analog signal outputs of the intake pipe pressure sensor 2 and the water temperature sensor 5 to adjust the level to the sampling level of the A/D converter 13. The output of this level correction circuit 12 is △/r)
It is converted into a digital signal by the converter 13 and sent to the CPU 1.
4.

Further, the output of the crank angle sensor 3 is input to the CPtJ 14 after being shaped by the waveform shaping circuit 11. The drive circuit 15 supplies fuel a equal to the fuel injection amount calculated by the CPU 14 to the engine by driving the fuel injection valve 6 in response to a signal output from the CPU 14 indicating the amount of fuel to be supplied to the engine. .

FIG. 3 is a flowchart showing the contents of the processing executed by the CPU 14. The operation of this embodiment will be explained below according to this flowchart.

This control routine starts in response to a pulse signal output from the crank angle sensor 3.

When this control routine starts, although not shown, the time of occurrence of the output pulse of the crank angle sensor 3, the intake pipe pressure detected by the intake pipe pressure sensor 2, and the water temperature detected by the water temperature sensor 5 are read. be exposed. First, in the process of step 21, it is determined whether or not it is time to start the engine. Here, "at the time of engine start" means that the engine speed is at a predetermined speed (after the starter starts operating).
For example, it refers to the state up to 500 rpm). If the determination in step 21 is YES, that is, it is time to start the engine, then the process in step 22 is executed.

The process of step 22 is a process of determining whether or not to calculate the first fuel injection amount when starting the engine. This is because the present embodiment employs a method in which the initial fuel supply amount increase correction at the time of engine startup is performed only at the time of the first fuel injection at engine startup. Therefore, in the case of a method in which the increase in the fuel supply amount at the initial stage of engine startup is performed during multiple fuel injections from the beginning at the time of engine startup, this step 22
Then, a process is executed to determine whether or not the number of calculations of fuel injection +a is equal to or less than a predetermined value (the number of times the fuel increase correction is performed).

If the determination in step 22 is YES, step 23
It is determined whether the predetermined flag x1 is 1 or not.

This flag x1 is used to determine whether or not the engine has been started again before the engine start is finished, and the flag x1 is set to 1 when the engine is restarted.

If the determination in step 23 is NO, it means that the engine is started by the first starting operation, not by restarting. Amount increase correction 1if[Fl
Calculate. This increase correction value is set to a larger value as the engine temperature becomes lower. Thereafter, in step 25, the flag x1 is set to 1. Here, this step 25 constitutes a temporary storage means for temporarily storing that the increase in the amount of fuel supplied at the initial stage of engine startup has been executed.

After executing the process in step 25, in step 27, the fuel injection amount TS at the time of engine starting is calculated 1), and in step 28
Then, the effective fuel injection amount TINJ is determined as the amount of fuel actually supplied to the engine.

This determined execution fuel injection ITINJ is determined by the drive circuit 1.
5, fuel equal to the effective fuel injection amount is supplied from the fuel injection valve 6 to the engine.

This effective fuel injection amount TINJ is obtained by multiplying the fuel l@ injection amount (hereinafter referred to as "calculated fuel injection amount" for distinction) TS divided in step 27 by (11F1). That is, the calculated fuel injection aiTs is increased by the increase correction value 1:1, and the value after this increase correction becomes the effective fuel injection ff1TINJ.

In this way, during the first fuel injection when the engine is started, which is not a restart, the fuel injection amount is increased in accordance with the engine temperature.

Next, if the engine is restarted by turning the ignition switch on and off or turning the starter on or off before the engine has finished starting,
When calculating the amount of fuel ll1tjJ for the first engine restart, the determination in step 22 is YES, but the determination in step 23 is NO, so the process of step 26 is executed, and the value of the fuel increase correction value F1 is Set to O.

After that, the processing of steps 27 and 28 is executed, so the effective fuel injection half INJ is set to the calculated fuel injection @mTs for which no increase correction is performed.

Therefore, each time the engine is restarted, the fuel injection 1) I
Increasing correction of ffi is prohibited. Here, the step 23 constitutes restart determination means for determining whether or not the engine has been started again before the engine start has ended, and the step 26 constitutes a restart determination means that determines whether or not the engine has been started again before the engine start has ended. This constitutes an increase prohibiting means that prohibits an increase in the amount of fuel supplied at the initial stage of engine startup when the engine is restarted.

Then, during the second and subsequent fuel injections when starting the engine, the determination at step 22 becomes NO, so step 26
Since the fuel increase correction value F1 is set to O by the process, the value of the effective fuel injection ITINJ calculated in step 28 becomes the value of the calculated fuel injection amount TS without the increase correction. This calculated fuel injection amount is calculated to gradually decrease as engine warm-up progresses, such as an increase in engine speed, for example.

Since the flag x1 is set in the backup RAM, its contents are saved even if the ignition key is turned off. Therefore, as described above, even if the ignition switch is repeatedly turned on and off at the end of the engine start, the increase correction of the fuel supply amount at the initial stage of the engine start is executed only once.

Then, when the engine starting is completed, the determination in step 21 becomes NO, so the process in step 29 is executed. This step 29 is a process for determining whether or not the elapsed time after starting the engine is equal to or longer than a predetermined time. This is a process executed in order to ensure the reliability of this determination when it is determined in step 21 that the engine starting has been completed, and step 5 is for confirming that the engine starting has been completely completed. When the determination in step 29 is YES, the flag x1 is set to 0 and cleared.

Therefore, if a restart operation is performed before a predetermined period of time has elapsed after the end of the engine start, even if the engine speed is equal to or higher than the predetermined value, the fuel increase correction at the initial stage of the engine start will not be performed.

The process of step 31 is a process of calculating the fuel injection a after engine startup, and includes the fuel injection amount to achieve the stoichiometric air-fuel ratio corresponding to the engine operating state, the increment of fuel supply t during acceleration, fuel cut, etc. Calculate the appropriate fuel injection amount in a state other than when starting the engine. This calculated fuel injection amount is determined by the drive circuit 1 as the effective fuel injection amount VJIA.
5.

Next, FIG. 4 is a flowchart showing another example of control for increasing the amount of fuel supplied at the time of starting the engine.

The control routine shown in the figure is an independent routine that only performs an increase correction of the fuel supply amount at the initial stage of engine startup. Therefore, the control routines for calculating the second and subsequent fuel injection times during other engine starts and for calculating the fuel injection amount after the engine starts are executed separately.

In step 41, it is determined whether or not the engine is started by processing similar to step 21. Step 42 is a process for determining whether or not the starter has been switched from off to on.
The off state is stored, and if it was off in the previous routine process and turned on in the current routine process, YES is determined.

Note that in step 42, instead of determining whether the starter is switched from off to on, processing may be performed to determine whether the ignition key is turned on or when the initialization of the CPU 14 is completed.

In the next step 43, by determining whether the flag x1 is set to 1, it is determined whether or not it is the first fuel injection amount at the time of starting the engine. If the determination in step 43 is No, the first
Since this is the time of the first fuel injection, step 44
Then, the fuel injection amount is determined to be equal to the value obtained by increasing the fuel injection amount corresponding to the water temperature at that time. In this example,
The fuel injection amount by the fuel injection valve 6 is calculated as the fuel injection amount. Then, in step 45, the calculated injection time T1 is output to the drive circuit 15, and the injection time T1 is
During this time, the fuel injection valve 6 is opened to supply fuel to the engine.

Thereafter, in step 46, the flag x1 is set to 1 to prohibit increasing correction of the fuel injection amount at the time of restart. Clearing this flag x1 is performed in a separate routine that calculates the fuel injection time after engine start.ffi l'l! This is performed in a routine (corresponding to the processing in steps 29 to 31).

Further, the valve closing process of the fuel l@injector 6 that has started the fuel injection is executed by an interrupt routine process using a clock-based counter in the CPIJ 14 when the fuel injection time T1 has elapsed.

(Effects of the Invention) As explained in detail above, the present invention prohibits an increase in the amount of fuel supplied at the initial stage of engine startup in response to the restart, even if the engine is restarted repeatedly before the engine startup is completed. This can prevent excess fuel from being supplied when starting the engine.

Therefore, engine startability is improved, ignition failure of the spark plug can be prevented, and unnecessary consumption of fuel can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, and FIG.
A block diagram showing the configuration of the control circuit in the figure.
FIG. 4 is a flowchart showing the contents of the process executed by the CPU in the figure, and FIG. 4 is a flowchart showing another example of the process executed by the CPU. 1... Intake pipe 2... Intake pipe pressure sensor 3... Crank angle sensor 4... Control circuit 5... Water temperature sensor 6. ...Fuel injection valve 10...Engine cylinder 14...CPU Fl...Fuel supply amount increase correction value TINJ...Executive fuel injection amount

Claims (1)

[Scope of Claims] A vehicle that determines the fuel supply amount according to the engine operating state, supplies an amount of fuel equal to the determined fuel supply amount to the engine, and increases the fuel supply amount at the initial stage when the engine is started. In the fuel supply amount control device for the engine, there is provided a temporary storage means for temporarily storing that the fuel supply amount has been increased during the initial stage of engine startup, and a start end means for determining that the engine startup has ended and the normal operating state has been reached. a determination means; a restart determination means for determining whether or not the engine has been started again before the start determination means determines that the engine start has ended; and a restart determination means for determining whether or not the engine has been started again; A vehicle fuel supply amount control device comprising: an increase prohibiting means for prohibiting an increase in the fuel supply amount at the initial stage of engine startup if it is determined that the engine has been restarted before the engine restart.